STILLWATER, Minn. — A medical examiner has testified in Washington County that a teenager’s baby was born alive, but died soon after from knife wounds.

The doctor testified in Nicole Beecroft’s second trial on charges of killing the newborn. Beecroft, now 24, spent seven years behind bars for killing the infant. But, her conviction and sentence were overturned last year when the Minnesota Supreme Court said Beecroft’s right to due process was violated. Beecroft has maintained the baby was stillborn.

The Star Tribune (http://bit.ly/1bMsfrN ) says Dr. Kelly Mills did an autopsy on the newborn in 2007 and testified Thursday that stab wounds were inflicted when the baby girl was alive. Mills said X-rays showed air in the baby’s lungs and stomach.

The defense got Mills to acknowledge that infants can inhale air and still die in the birth canal.